It has been attempted in a known combustion engine to improve the mixture-formation, and, accordingly, combustion during idling in the lower speed range and in the lower load range, whereby the fuel injected under these conditions is mixed with the combustion air directly, because the required temperatures, i.e. the temperature required for the particular combustion technique and the temperature required on the combustion chamber wall, for a sufficiently rapid evaporation or combustion of the fuel deposited as a film were not present, which was confirmed by the poor quality of the exhaust gases and the resulting engine data.
In order to overcome this drawback, a number of proposals have been set forth. However, all these proposals have entailed still further drawbacks. Thus, either the arrangements involved were too expensive or too complicated, or the advantages which are realized when depositing the fuel on the combustion chamber wall at the upper operating range of the engine, were offset in part because of detrimental developments.
Internal combustion engines as briefly described in the foregoing have brought about a true improvement with simple, yet effective means but it has been shown that the degree of spraying or atomization of the fuel should be increased during the lower operating ranges of such engines in order to realize further improvements.